Various Aspects of the Interfacial Self-Assembly of Nanoparticles

Abstract

We describe the interfacial self-assembly of nanoparticles at liquid–liquid interfaces and in block copolymers. At the interface of two immiscible liquids, the particles assemble into disordered but densely packed monolayers. This self-assembly process was investigated ex situ with scanning force microscopy (SFM) and transmission electron microscopy (TEM), and laser scanning confocal microscopy (LCSM) methods. Adsorbed particles can be crosslinked at the interface to fabricate mechanically stable capsules and membranes. In addition, it was shown by pendant drop tensiometry that Janus particles consisting of gold and iron oxide show a significantly higher interfacial activity than homogeneous gold or iron oxide nanoparticles of comparable size and chemical nature. For the self-assembly of nanoparticles in block copolymer mixtures, it was shown theoretically and experimentally that these composite materials form hierarchically ordered structures. Therefore, thin films from mixtures of a cylindrical polystyrene-block-poly(2-vinylpyridine), with tri-n-octylphosphine oxide-covered CdSe nanoparticles were prepared and investigated with SFM, TEM, and grazing-incidence small angle x-ray scattering (GISAXS) after thermal annealing.